The present disclosure relates to one or more features on the surface, such as the top surface, of a solid ink stick that increase the ease of removal of an ink stick from an ink feed channel of an imaging device.
Certain imaging devices, such as solid ink or phase change ink printers, conventionally receive ink in a solid form, either as pellets or as ink sticks. The solid ink pellets or ink sticks are typically inserted through an insertion opening of an ink loader for the printer, and the ink sticks are pushed or slid along the feed channel by a feed mechanism and/or gravity toward a heater plate in the heater assembly. The heater plate melts the solid ink impinging on the plate into a liquid that is delivered to a print head for jetting onto a recording medium.
The correct loading and feeding of ink sticks has typically been accomplished by incorporating keying, guiding, alignment, or orientation features into the exterior surface of an ink stick. These keying features are protuberances or indentations that are located in different positions on an ink stick. Corresponding keys or guide elements on the perimeters of the insertion openings exclude ink sticks which do not have the appropriate perimeter key elements, and also ensure that the ink stick is properly aligned and oriented in the feed channel. These keying features are particularly important for color printers, which typically use four different colors of ink (cyan, yellow, magenta, and black).
The physical configuration of the ink stick generally provides all of the uniqueness to determine whether the ink stick is in the proper feed channel. However, this system is not foolproof, largely because the keying features are not extreme in their depths to avoid mass loss and reduce the vulnerability of the ink stick to fracture. Because the keying features are moderate and can be very similar across multiple product lines, incorrect insertions can occur. For example, because cyan, magenta, and black ink sticks are somewhat similar in color, they can be easily loaded into the incorrect feed channel. Even if an ink stick is placed in the correct feed channel, the ink stick may not be correctly oriented. An incorrectly oriented ink stick may not feed properly along the feed channel and/or may not engage the ink melter appropriately. In addition, encoding features on an ink stick that has been incorrectly oriented may not be positioned optimally in the feed channel to interact with sensors, resulting in faulty actuation of the sensors or no actuation at all. This causes a need to remove the ink stick out of the feed channel through the insertion opening.
Insertion openings typically offer very small clearances, and ink sticks are not generally shaped to enhance retrieval. U.S. Pat. No. 6,929,360 describes one method of retrieving an ink stick. The insertion opening itself is shaped to both provide guide elements and to provide a clearance space through which a tweezer-like removal tool can be inserted to grasp the ink stick and pull the ink stick through the insertion opening.
It would be desirable to provide an ink stick with integrated retrieval features, allowing the ink stick to be removed through the insertion opening with the human hand alone, i.e. without the need for additional tools.